Modular vascular graft for low profile percutaneous delivery

ABSTRACT

A hybrid modular endovascular graft wherein a main graft is sized to span at least a portion of a target vessel lesion in a large percentage of patients. Graft extensions may be secured to the main graft to extend the main graft and provide a sealing function for some applications.

RELATED APPLICATION

This application claims priority under 35 U.S.C. section 119(e) fromU.S. provisional application Ser. No. 60/977,617 filed Oct. 4, 2007, byMichael V. Chobotov et al. titled “MODULAR VASCULAR GRAFT FOR LOWPROFILE PERCUTANEOUS DELIVERY” which is incorporated by reference hereinin its entirety.

BACKGROUND

An aneurysm is a medical condition indicated generally by an expansionand weakening of the wall of an artery of a patient. Aneurysms candevelop at various sites within a patient's body. Thoracic aorticaneurysms (TAAs) or abdominal aortic aneurysms (AAAs) are manifested byan expansion and weakening of the aorta which is a serious and lifethreatening condition for which intervention is generally indicated.Existing methods of treating aneurysms include invasive surgicalprocedures with graft replacement of the affected vessel or body lumenor reinforcement of the vessel with a graft.

Surgical procedures to treat aortic aneurysms can have relatively highmorbidity and mortality rates due to the risk factors inherent tosurgical repair of this disease as well as long hospital stays andpainful recoveries. This is especially true for surgical repair of TAAs,which is generally regarded as involving higher risk and more difficultywhen compared to surgical repair of AAAs. An example of a surgicalprocedure involving repair of a AAA is described in a book titledSurgical Treatment of Aortic Aneurysms by Denton A. Cooley, M.D.,published in 1986 by W.B. Saunders Company.

Due to the inherent risks and complexities of surgical repair of aorticaneurysms, endovascular repair has become a widely-used alternativetherapy, most notably in treating AAAs. Early work in this field isexemplified by Lawrence, Jr. et al. in “Percutaneous Endovascular GraftExperimental Evaluation”, Radiology (May 1987) and by Mirich et al. in“Percutaneously Placed Endovascular Grafts for Aortic Aneurysms:Feasibility Study,” Radiology (March 1989). Commercially availableendoprostheses for the endovascular treatment of AAAs include theAneuRx® stent graft manufactured by Medtronic, Inc. of Minneapolis,Minn., the Zenith® stent graft system sold by Cook, Inc. of Bloomington,Ind., the PowerLink® stent-graft system manufactured by Endologix, Inc.of Irvine, Calif., and the Excluder® stent graft system manufactured byW.L. Gore & Associates, Inc. of Newark, Del. A commercially availablestent graft for the treatment of TAAs is the TAG™ system manufactured byW.L. Gore & Associates, Inc.

When deploying devices by catheter or other suitable instrument, it isadvantageous to have a flexible and low profile stent graft and deliverysystem for passage through the various guiding catheters as well as thepatient's sometimes tortuous anatomy. Many of the existing endovasculardevices and methods for treatment of aneurysms, while representingsignificant advancement over previous devices and methods, use systemshaving relatively large transverse profiles, often up to 24 French.Also, such existing systems have greater than desired lateral stiffness,which can complicate the delivery process. In addition, the sizing ofstent grafts may be important to achieve a favorable clinical result. Inorder to properly size a stent graft, the treating facility typicallymust maintain a large and expensive inventory of stent grafts in orderto accommodate the varied sizes of patient vessels due to varied patientsizes and vessel morphologies. Alternatively, intervention may bedelayed while awaiting custom size stent grafts to be manufactured andsent to the treating facility. As such, minimally invasive endovasculartreatment of aneurysms is not available for many patients that wouldbenefit from such a procedure and can be more difficult to carry out forthose patients for whom the procedure is indicated. What has been neededare stent graft systems and methods that are adaptable to a wide rangeof patient anatomies and that can be safely and reliably deployed usinga flexible low profile system.

SUMMARY

Some embodiments of a modular endovascular graft assembly include abifurcated main graft member formed from a supple graft material havinga main fluid flow lumen therein. The main graft member may also includean ipsilateral leg with an ipsilateral fluid flow lumen in communicationwith the main fluid flow lumen, a contralateral leg with a contralateralfluid flow lumen in communication with the main fluid flow lumen and anetwork of inflatable channels disposed on the main graft member. Thenetwork of inflatable channels may be disposed anywhere on the maingraft member including the ipsilateral and contralateral legs. Thenetwork of inflatable channels may be configured to accept a hardenablefill or inflation material to provide structural rigidity to the maingraft member when the network of inflatable channels is in an inflatedstate. The network of inflatable channels may also include at least oneinflatable cuff disposed on a proximal portion of the main graft memberwhich is configured to seal against an inside surface of a patient'svessel. The fill material can also have transient or chronic radiopacityto facilitate the placement of the modular limbs into the main graftmember. A proximal anchor member may be disposed at a proximal end ofthe main graft member and be secured to the main graft member. Theproximal anchor member may have a self-expanding proximal stent portionsecured to a self-expanding distal stent portion with struts having across sectional area that is substantially the same as or greater than across sectional area of proximal stent portions or distal stent portionsadjacent the strut. At least one ipsilateral graft extension having afluid flow lumen disposed therein may be deployed with the fluid flowlumen of the graft extension sealed to and in fluid communication withthe fluid flow lumen of the ipsilateral leg of the main graft member. Atleast one contralateral graft extension having a fluid flow lumendisposed therein may be deployed with the fluid flow lumen of the graftextension sealed to and in fluid communication with the fluid flow lumenof the contralateral leg of the main graft member. For some embodiments,an outside surface of the graft extension may be sealed to an insidesurface of the contralateral leg of the main graft when the graftextension is in a deployed state. For some embodiments, the axial lengthof the ipsilateral and contralateral legs may be sufficient to provideadequate surface area contact with outer surfaces of graft extensions toprovide sufficient friction to hold the graft extensions in place. Forsome embodiments, the ipsilateral and contralateral legs may have anaxial length of at least about 2 cm. For some embodiments, theipsilateral and contralateral legs may have an axial length of about 2cm to about 6 cm, more specifically, about 3 cm to about 5 cm.

Some embodiments of a modular endovascular graft assembly include abifurcated main graft member having an axial length of about 5 cm toabout 10 cm formed from a supple graft material. The main graft memberhas a main fluid flow lumen therein, an ipsilateral leg with anipsilateral fluid flow lumen in communication with the main fluid flowlumen and with an axial length of at least about 2 cm, a contralateralleg with a contralateral fluid flow lumen in communication with the mainfluid flow lumen and with an axial length of at least about 2 cm. Themain graft member also includes network of inflatable channels disposedon the main graft member, including the ipsilateral and contralaterallegs, which is configured to accept a hardenable fill material toprovide structural rigidity to the main graft member when the network ofinflatable channels are in an inflated state. The network of inflatablechannels may also include at least one inflatable cuff disposed on aproximal portion of the main graft member configured to seal against aninside surface of a patient's vessel. A proximal anchor member may bedisposed at a proximal end of the main graft member and secured to themain graft member. The proximal anchor member may have a self-expandingproximal stent portion secured to a self-expanding distal stent portionwith struts. At least one ipsilateral graft extension having a fluidflow lumen disposed therein may have the fluid flow lumen of the graftextension sealed to and in fluid communication with the fluid flow lumenof the ipsilateral leg of the main graft member. At least onecontralateral graft extension having a fluid flow lumen disposed thereinmay have the fluid flow lumen of the graft extension sealed to and influid communication with the fluid flow lumen of the contralateral legof the main graft member.

Some embodiments of a method of treating a patient include providing adelivery catheter containing a radially constrained bifurcated maingraft member. The main graft member may be formed from a supple graftmaterial which has a main fluid flow lumen therein and which has anipsilateral leg with an ipsilateral fluid flow lumen in communicationwith the main fluid flow lumen and a contralateral leg with acontralateral fluid flow lumen in communication with the main fluid flowlumen. The main graft member may also include a network of inflatablechannels disposed on the main graft member. Inflatable channels of thenetwork of inflatable channels may be disposed on any portion of themain graft member including the ipsilateral and contralateral legs ofthe main graft member. The main graft member may also include a proximalanchor member which is disposed at a proximal end of the main graftmember and secured to the main graft member. The proximal anchor membermay have a self-expanding proximal stent portion secured to aself-expanding distal stent portion. Such a delivery catheter may beaxially positioned within the patient's vasculature such that the maingraft member within the delivery catheter is disposed coextensively witha vascular defect of the patient's aorta. Once this positioning has beenachieved, the proximal anchor member may be deployed so as to radiallyexpand and engage an inner surface of the patient's vasculature andanchor the proximal anchor member to the patient's aorta. Thereafter,the network of inflatable channels of the main graft member may beinflated with an inflation material so as to provide a more mechanicallyrigid structure of the main graft member. For some embodiments,inflation of the network of inflatable channels may also provide a sealbetween an outer surface of an inflatable cuff of the main graft memberand an inside surface of the patient's body lumen in contact with theinflatable cuff. For some embodiments, a hardenable fill material may beused that may assume or more solid configuration after inflation of thenetwork of inflatable channels so as to provide additional mechanicalrigidity as well as prevent leakage of the fill material. Someembodiments may also employ radiopaque inflation material to facilitatemonitoring of the fill process and subsequent engagement of graftextensions. A second delivery catheter containing a radially constrainedself-expanding contralateral graft extension may then be axiallypositioned in the contralateral leg of the main graft member with aproximal portion of the contralateral graft extension axially overlappedwith an inner fluid flow lumen of the contralateral leg of the maingraft member and a distal portion of the contralateral graft extensionaxially overlapped with a portion of the patient's contralateral iliacartery. Access to the contralateral leg of the main graft portion may beachieved by percutaneous access or femoral arteriotomy from thepatient's contralateral femoral artery with a delivery sheath or thelike. Once properly positioned, the self-expanding contralateral graftextension may be deployed by releasing the radial constraint of thesecond delivery catheter. As the contralateral graft extension selfexpands in an outward radial orientation, a seal between the inner fluidflow lumen of the contralateral graft extension, a fluid flow lumen ofthe contralateral leg and a fluid flow lumen of the contralateral iliacartery may be formed. A third delivery catheter containing a radiallyconstrained self-expanding ipsilateral graft extension may also beaxially positioned in the ipsilateral leg of the main graft member witha proximal portion of the ipsilateral graft extension axially overlappedwith an inner fluid flow lumen of the ipsilateral leg of the main graftmember and a distal portion of the ipsilateral graft extension axiallyoverlapped with a portion of the patient's ipsilateral iliac artery. Theself-expanding ipsilateral graft extension may then be deployed byreleasing the radial constraint so as to form a seal between the innerfluid flow lumen of the ipsilateral graft extension, a fluid flow lumenof the ipsilateral leg and a fluid flow lumen of the ipsilateral iliacartery. The ipsilateral and contralateral graft extensions may bedelivered and deployed in either order.

Some embodiments of a graft extension include a fluid flow lumendisposed therein, at least one layer of permeable PTFE material, atleast one layer of semi-permeable or substantially non-permeable PTFEmaterial having no discernable node and fibril structure and aninterposed self-expanding stent formed from an elongate resilientelement helically wound with a plurality of longitudinally spaced turnsinto an open tubular configuration disposed between at least one outerlayer and at least one inner layer of PTFE material.

These features of embodiments will become more apparent from thefollowing detailed description when taken in conjunction with theaccompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevation view of a modular graft assembly.

FIG. 1A is an elevation view of a proximal anchor member and connectorring of the modular graft assembly.

FIG. 2 is a transverse cross section of the modular graft assembly ofFIG. 1 taken along lines 2-2 of FIG. 1.

FIG. 3 is a transverse cross section of the modular graft assembly ofFIG. 1 taken along lines 3-3 of FIG. 1.

FIG. 4 is a transverse cross section of the graft extension of themodular graft assembly of FIG. 1 taken along lines 4-4 of FIG. 1.

FIG. 4A is an enlarged view of a junction between a graft extension andan ipsilateral leg of the graft assembly of FIG. 1 indicated by theencircled portion 4A-4A in FIG. 1.

FIG. 5A is an enlarged view of a junction between a proximal anchormember and connector ring of FIG. 1 indicated by the encircled portion5A-5A in FIG. 1.

FIG. 5B is an exploded view of a junction between connector elements ofthe proximal anchor member and connector ring without a coil member.

FIG. 6A is an enlarged view of a junction between a distal stent portionand a proximal stent portion of the proximal anchor member of FIG. 1indicated by the encircled portion 6A-6A in FIG. 1.

FIG. 6B is a transverse cross section of the proximal anchor member ofthe modular graft assembly of FIG. 1 taken along lines 6B-6B of FIG. 6A.

FIG. 6C is a transverse cross section of the proximal anchor member ofthe modular graft assembly of FIG. 1 taken along lines 6C-6C of FIG. 6A.

FIG. 6D is a transverse cross section of the proximal anchor member ofthe modular graft assembly of FIG. 1 taken along lines 6D-6D of FIG. 6A.

FIGS. 7-14 illustrate a deployment sequence of a modular graft systemwithin the vasculature of a patient.

FIG. 15 is an elevation view of an embodiment of a graft extension.

FIG. 16 is a transverse cross sectional view of the graft extension ofFIG. 15 taken along lines 16-16 of FIG. 15.

FIGS. 17A to 17E illustrate embodiments of graft extensionconfigurations.

DETAILED DESCRIPTION

Embodiments of the invention are directed generally to methods anddevices for treatment of fluid flow vessels with the body of a patient.Treatment of blood vessels is specifically indicated for someembodiments, and, more specifically, treatment of aneurysms, such asabdominal aortic aneurysms.

Some embodiments of a modular endovascular graft assembly may include abifurcated main graft member formed from a supple graft material, suchas ePTFE, having a main fluid flow lumen therein. The main graft membermay also include an ipsilateral leg with an ipsilateral fluid flow lumenin communication with the main fluid flow lumen, a contralateral legwith a contralateral fluid flow lumen in communication with the mainfluid flow lumen and a network of inflatable channels disposed on themain graft member. For some embodiments, the main graft member may havean axial length of about 5 cm to about 10 cm, more specifically, about 6cm to about 8 cm in order to span an aneurysm of a patient's aortawithout engaging the patient's iliac arteries directly with the legs ofthe main graft member.

The inflatable channels of the network of inflatable channels may bedisposed on any portion of the main graft member including theipsilateral and contralateral legs. The network of inflatable channelsmay be configured to accept a hardenable fill material to providestructural rigidity to the main graft member when the network ofinflatable channels are in an inflated state and the inflation materialhas been cured or hardened. Radiopaque inflation material may be used tofacilitate monitoring of the fill process and subsequent engagement ofgraft extensions. The network of inflatable channels may also include atleast one inflatable cuff disposed on a proximal portion of the maingraft member which is configured to seal against an inside surface of apatient's vessel, such as the aorta.

A proximal anchor member is disposed at a proximal end of the main graftmember and secured to the main graft member. The proximal anchor memberhas a self-expanding proximal stent portion secured to a self-expandingdistal stent portion with struts. Some embodiments of the struts mayhave a cross sectional area that is substantially the same as or greaterthan a cross sectional area of proximal stent portions or distal stentportions adjacent the strut. Such a configuration may be useful inavoiding points of concentrated stress in the proximal anchor member orstruts which couple components thereof. For some embodiments, theproximal stent of the proximal anchor member further includes aplurality of barbs having sharp tissue engaging tips that are configuredto extend in a radial outward direction in a deployed expanded state.For some embodiments, the proximal anchor member includes a 4 crownproximal stent portion and a 8 crown distal stent portion which may bemade from a superelastic alloy such as superelastic NiTi alloy.

At least one ipsilateral graft extension having a fluid flow lumendisposed therein may be deployed with the fluid flow lumen of the graftextension sealed to and in fluid communication with the fluid flow lumenof the ipsilateral leg of the main graft member. In addition, at leastone contralateral graft extension having a fluid flow lumen disposedtherein may be deployed with the fluid flow lumen of the graft extensionsealed to and in fluid communication with the fluid flow lumen of thecontralateral leg of the main graft member. For some embodiments, thegraft extensions may include an interposed self-expanding stent disposedbetween at least one outer layer and at least one inner layer of supplelayers of graft material. The interposed stent disposed between theouter layer and inner layer of graft material may be formed from anelongate resilient element helically wound with a plurality oflongitudinally spaced turns into an open tubular configuration. For someembodiments, the interposed stent is may include a superelastic alloysuch as superelastic NiTi alloy. In addition, the graft material of eachgraft extension may further include at least one axial zone of lowpermeability for some embodiments.

For some embodiments, an outside surface of the graft extension may besealed to an inside surface of the contralateral leg of the main graftwhen the graft extension is in a deployed state. For some embodiments,the axial length of the ipsilateral and contralateral legs may besufficient to provide adequate surface area contact with outer surfacesof graft extensions to provide sufficient friction to hold the graftextensions in place. For some embodiments, the ipsilateral andcontralateral legs may have an axial length of at least about 2 cm. Forsome embodiments, the ipsilateral and contralateral legs may have anaxial length of about 2 cm to about 6 cm, more specifically, about 3 cmto about 5 cm.

FIGS. 1-6 show a bifurcated embodiment of a modular graft assembly 10for treatment of an abdominal aortic aneurysm. The graft assembly 10includes a bifurcated main graft member 12, an ipsilateral graftextension 14 and contralateral graft extension 15. The main graft 12 hasa wall portion 16 that bounds a main fluid flow lumen 18 disposedtherein. An ipsilateral leg 20 of the main graft 12 has a ipsilateralport 22 and an ipsilateral fluid flow lumen 24 that is in fluidcommunication with the main fluid flow lumen 18 and the ipsilateral port22. A contralateral leg 26 of the main graft 12 has a contralateral port28 and a contralateral fluid flow lumen 30 that is in fluidcommunication with the main fluid flow lumen 18 and the contralateralport 28. The main graft 12, ipsilateral leg 20 and contralateral leg 26form a bifurcated “Y” shaped configuration.

The main fluid flow lumen 18 (shown in FIG. 2) of the main graft 12generally may have a larger transverse dimension and area than atransverse dimension and area of either of the fluid flow lumens 24 and30 (shown in FIG. 3) of the ipsilateral leg 20 or contralateral leg 26,respectively. A proximal anchor member 32 is disposed at a proximal end31 of the main graft 12. The proximal anchor member 32 includes aproximal self-expanding stent 32A that is formed from an elongateelement having a generally serpentine shape with four crowns or apicesat either end. Each proximal apex or crown of the proximal stent 32A iscoupled to alternating distal crowns or apices of an 8 crown distalself-expanding stent 32B. The distal self-expanding stent is formed froman elongate element having a generally serpentine shape. A distal end ofthe distal stent 32B may be mechanically coupled to a connector ringwhich is embedded in graft material of the proximal end of the maingraft 12, or directly coupled to perforations in the proximal edgeregion of the main graft. Embodiments of the connector ring may begenerally circular in shape have regular undulations about thecircumference that may be substantially sinusoidal in shape. Theproximal stent 32A includes outwardly extending barbs 33, that may beintegrally formed with the struts of the stent for some embodiments,having sharp tissue penetrating tips that are configured to penetrateinto tissue of an inside surface of a lumen within which the proximalstent 32A is deployed in an expanded state. Although the proximal anchormember 32 is shown as including self-expanding stents 32A and 32B,similar stents may be used that are configured to be inelasticallyexpanded with outward radial pressure as might be generated by theexpansion of an expandable balloon from within either or both stents 32Aand 32B. The connector ring coupled to the proximal stent 32B may alsobe inelastically expandable.

With regard to graft embodiments discussed herein, such as graftassembly 10, and components thereof, as well as graft extensions 14 and15, the term “proximal” refers to a location towards a patient's heartand the term “distal” refers to a location away from the patient'sheart. With regard to delivery system catheters and components thereofdiscussed herein, the term “distal” refers to a location that isdisposed away from an operator who is using the catheter and the term“proximal” refers to a location towards the operator.

The ipsilateral graft extension 14 has a fluid flow lumen 44 disposedtherein. The ipsilateral graft extension 14 has an outer surface whichmay be sized and configured to be sealed to an inside surface of theipsilateral leg of the main graft with the inner fluid flow lumen 44 ofthe ipsilateral graft extension 14 in fluid communication with the fluidflow lumen 24 of the ipsilateral leg 20. Typically, an outside surface46 of the graft extension 14 may be sealed to an inside surface 48 ofthe ipsilateral leg 20 of the main graft 12 when the graft extension 14is in a deployed state. The contralateral graft extension 15 has a fluidflow lumen 45 disposed therein. The contralateral graft extension 15 hasan outer surface 47 which may be sized and configured to be sealed to aninside surface 50 of the contralateral leg 26 of the main graft 12 withthe inner fluid flow lumen 45 in fluid communication with the fluid flowlumen 30 of the contralateral leg 26. Typically, an outside surface 47of the graft extension 15 may be sealed to an inside surface 50 of thecontralateral leg 26 of the main graft 12 when the graft extension 15 isin a deployed state. For some embodiments, the axial length of theipsilateral and contralateral legs 20 and 26 may be sufficient toprovide adequate surface area contact between outer surfaces 46 and 47of graft extensions 14 and 15 and respective inside surfaces 48 and 50of the legs 20 and 26 to provide sufficient friction to hold the graftextensions 14 and 15 in place. Varying the amount of overlap between thelegs and extensions can allow for different effective overall graftlengths to be achieved, thereby accommodating a range of anatomicalsizes with fewer distinct main body and extension dimensions than wouldotherwise be required. For some embodiments, the ipsilateral andcontralateral legs 20 and 26 may have an axial length of at least about1 cm. For some embodiments, the ipsilateral and contralateral legs 20and 26 may have an axial length of about 2 cm to about 6 cm, morespecifically, about 3 cm to about 5 cm.

The graft extensions 14 and 15 may be formed from an inner layer orlayers and outer layer or layers of flexible graft material, such asPTFE or ePTFE. The inner and outer layers of graft material may beformed from tubular extrusions, laminated wraps of multiple layers ofgraft material or materials, and the like. The inner or outer layers ofgraft material may be permeable, semi-permeable or substantiallynon-permeable for some embodiments. For some embodiments, the nominallength of the extensions 14 and 15 may be permeable with one or morelongitudinal sections, such as a middle longitudinal section, beingsemi-permeable or non-permeable. Some embodiments of the graftextensions 14 and 15 may have an overall tapered or flared configurationwith a nominal inner lumen that tapers or flares when the graftextension is in a relaxed expanded state. For embodiments that includelaminated wraps of material, the wraps may be carried outcircumferentially, helically or in any other suitable configuration.

A radially expandable stent 51 may be interposed between the outer layer54 and inner layer 56 of graft material of extensions 14 and 15. Theinterposed stent disposed between the outer layer and inner layer ofgraft material may be formed from an elongate resilient elementhelically wound with a plurality of longitudinally spaced turns into anopen tubular configuration. The helically wound stent 51 may beconfigured to be a self-expanding stent or radially expandable in aninelastic manner actuated by an outward radial force from a device suchas an expandable balloon or the like. Some tubular prosthesisembodiments that may be used for graft extensions 14 and 15 arediscussed in U.S. Pat. No. 6,673,103 to Golds et al., filed May 16, 2000titled “Mesh and Stent for Increased Flexibility”, which is herebyincorporated by reference in its entirety herein.

The graft extensions 14 and 15 may optionally include attachmentelements disposed on outer surfaces 46 and 47 (shown in FIG. 3) of theirrespective proximal ends or sections that may be used to couple tocorresponding attachment elements disposed on inside surfaces of therespective ipsilateral leg 20 and contralateral leg of the main graft12. Attachment element embodiments that may be used on outside surfaces46 and 47 of the graft extensions 14 and 15 and inside surfaces 48 and50 of legs 20 and 26 of the main graft 12 may include any of theattachment elements in International Patent Application No.PCT/US2005/008119, entitled “Modular Endovascular Graft”, filed Mar. 11,2005, by Stephens, et al., published Sep. 22, 2005, which is herebyincorporated by reference herein in its entirety. Some embodiments ofmodular grafts such as system 10 having attachment elements may includea first graft body section such as graft main body 12 and a second graftbody section such as extensions 14 and 15. The first graft body sectionmay have a first wall portion and a first attachment element disposed onthe first wall portion and the second graft body section may have asecond attachment element disposed on a second wall portion of thesecond graft body section. The second attachment element may beconfigured to be secured to the first attachment element with respectivefluid flow lumens of the first and second graft body sections sealedtogether. For some embodiments, the first and second attachment elementsmay be secured together in an overlapped portion of the first and secondgraft body sections. For some embodiments, the first attachment elementmay include a plurality of flexible hooks and the second attachmentelement includes a plurality of flexible loops adjacent each otherwherein the flexible hooks are configured to mechanically engage theflexible loops when the first and second attachment elements are pressedtogether. For some embodiments, the first attachment element includes aplurality of buttons having an enlarged head portion regularly spacedfrom each other on a surface a first wall portion and a secondattachment element includes an expandable mesh having a plurality ofapertures configured to allow entry of the enlarged head portion of thebuttons while the mesh is in a circumferentially constrained state andto capture the enlarged head portion of the buttons when the mesh is ina circumferentially expanded state. For some embodiments, the firstattachment element includes a plurality of pins radially extending froma surface of a first wall portion and the second attachment elementincludes an expandable mesh having a plurality of apertures configuredto allow entry of the pins when the first attachment element is pressedagainst the second attachment element. For some embodiments the firstattachment element may include an inflatable cuff containing curablematerial and the second attachment element includes an expandable memberwith barbs configured to extend outwardly into the inflatable cuff andcurable material.

The transverse dimension or diameter of the main fluid flow lumen 18 ofsome main graft embodiments 12 in a radially expanded state may be fromabout 12.0 mm to about 32.0 mm. The transverse dimension or diameter ofthe ipsilateral and contralateral fluid flow lumens 24 and 30 of therespective ipsilateral leg 20 and contralateral leg 26 may be from about5 mm to about 20 mm for some embodiments. The axial length of thecontralateral leg 26 is indicated by arrow 57 in FIG. 1. For someembodiments, the length of the legs 20 and 26 and may be from about 2 cmto about 6 cm. The transverse dimension of some embodiments of the graftextensions 14 and 15 when in a radially expanded state may be from about5 mm to about 26 mm. The axial length of some embodiments of the graftextensions 14 and 15 may be from about 2 cm to about 15 cm,specifically, about 5 cm to about 10 cm. Some embodiments of theipsilateral and contralateral extension grafts 14 and 15 may have outertransverse dimensions or diameters of between about 10 mm to about 30mm, more specifically, between about 15 mm and 25 mm when in an expandedstate.

The main graft 12 and ipsilateral graft extensions 14 and 15 may be madeat least partially from polytetrafluoroethylene (PTFE) which may includeexpanded polytetrafluoroethylene (ePTFE). In particular, main graft 12and graft extensions 14 and 15 may include any number of layers of PTFEand/or ePTFE, including from about 2 to about 15 layers, having anuncompressed layered thickness of about 0.003 inch to about 0.015 inchfor the supple graft material or materials alone without supporting orancillary structures such as high strength stents, connector rings orthe like. Unless otherwise specifically stated, the term “PTFE” as usedherein includes PTFE, porous PTFE and ePTFE, any of which may beimpermeable, semi-permeable, or permeable. Furthermore, the graftassembly and any portions thereof including the main body and extensionsdescribed herein may include all PTFE, all ePTFE, or a combinationthereof. Such graft body sections may also include any alternative highstrength, supple biocompatible materials, such as DACRON, suitable forgraft applications. Descriptions of various constructions of graft bodysections as well as other components of graft assembly 10 that may beused in any suitable combination for any of the embodiments discussedherein may be found in U.S. patent application Ser. No. 10/029,557,publication US 2003/0116260 A1, filed Dec. 20, 2001 by Chobotov, et al.,entitled “Method and Apparatus for Manufacturing an Endovascular GraftSection”, U.S. patent application Ser. No. 10/029,584, filed Dec. 20,2001 by Chobotov et al., entitled “Endovascular Graft Joint and Methodof Manufacture”, U.S. patent application Ser. No. 10/029,559, entitled“Method and Apparatus for Shape Forming Endovascular Graft Material”,filed on Dec. 20, 2001 by Chobotov et al., U.S. Pat. No. 7,147,660,filed Dec. 20, 2002, by Chobotov et al., entitled “Advanced EndovascularGraft”, U.S. patent application Ser. No. 11/106,131, publication US2006/0233990A1, filed Apr. 13, 2005, by Humphrey et al. entitled “PTFELayers and Methods of Manufacturing”, and U.S. patent application Ser.No. 11/106,150, publication US 2006/0233991, filed Apr. 13, 2005, byHumphrey et al., entitled “PTFE Layers and Methods of Manufacturing”,the entirety of each of which is incorporated herein by reference.

The laminated structure of various portions of the graft member 12,including ipsilateral and contralateral legs 20 and 26, extensions 14and 15, or all of these, may include a variety of configurations whereinlaminate materials having similar but different properties may be usedtogether or individually. For example, some embodiments of a main bodyportion of the graft member 12 may have a laminated structure of about 1layer to about 5 layers of porous ePTFE material having a mean nodalspacing of about 5 microns to about 35 microns, more specifically, about10 microns to about 25 microns, and a thickness of about 0.0002 inchesto about 0.002 inches, more specifically, about 0.0005 inches to about0.0015 inches. The main body portion of the graft member 12 may alsoinclude about 1 layer to about 5 layers of semi-permeable PTFE having afirst permeability and a thickness of about 0.0002 inches to about 0.002inches, more specifically, about 0.0004 inches to about 0.001 inches.The main body portion may also include about 1 layer to about 5 layersof semi-permeable PTFE material having a second permeability differentfrom the first permeability and a thickness of about 0.0002 inches toabout 0.002 inches, more specifically, about 0.0004 inches to about0.001 inches. Any suitable embodiments of the semi-permeable layers ofPTFE discussed in U.S. Patent Applications 2006/0233990 and2006/0233991, incorporated by reference above, may be used in theseembodiments. The main body portion may also include about 1 layer toabout 5 layers of PTFE having essentially no nodal spacing and very lowor no liquid permeability and a thickness of about 0.0001 inches toabout 0.0015 inches, more specifically, about 0.0002 inches to about0.001 inches.

For embodiments of modular graft systems that do not include theattachment elements, outside surfaces 46 and 47 of the proximal ends ofthe graft extensions 14 and 15 may be expanded against the insidesurfaces 48 and 50, respectively, of the fluid flow lumens of legs 20and 26 of the graft member 12. This configuration may be used to sealthe fluid flow lumens 44 and 45 of the graft extensions 14 and 15 to thefluid flow lumens 24 and 30 of the legs 20 and 26. Expandable members,such as expandable anchor members and the like, may be used to expandthe graft extensions 14 and 15 against the inside surfaces 48 and 50 ofthe fluid flow lumens 24 and 30 of the legs 20 and 26.

A network of inflatable elements or channels 58 is disposed on the maingraft 12 which may be inflated under pressure with an inflation material(not shown) through a main fill port 60 that has a lumen disposedtherein in fluid communication with the network of inflatable channels58. The inflation material may be retained within the network ofinflatable channels 58 by a one way-valve (not shown), disposed withinthe lumen of the main fill port 60. The network of inflatable channels58 may optionally be filled with a hardenable material that may beconfigured to harden, cure or otherwise increase in viscosity or becomemore rigid after being injected into the channels. Hardenable inflationmaterials such as gels, liquids or other flowable materials that arecurable to a more solid or substantially hardened state may be used toprovide mechanical support to the main graft 12 and legs by virtue ofthe mechanical properties of the hardened material disposed within thechannels. The network of inflatable channels 58 may also providestructural support to the main graft 12 when in an inflated state due tothe stiffness of the channels created by the increased interior pressurewithin the channels even if a non-hardenable inflation material, such assaline or the like, is used so long as an increased interior pressurecan be maintained. Such an increase in stiffness or rigidity may beuseful for a variety of purposes. For example, during deployment,inflation of the network of inflatable channels may urge the main graftbody including the main flow channel and legs thereof to conform to agenerally cylindrical configuration having open flow lumens which may beuseful when attempting to locate and navigate the flow lumens of thecontralateral or ipsilateral leg with a delivery catheter, guidewire orthe like. Such location and navigation of the flow lumens of the maingraft body and portions thereof may also be facilitated by the use ofradiopaque inflation materials that provide enhanced visualization underfluoroscopic imaging.

The network of inflatable channels 58 may include one or morecircumferential channels disposed completely or partially about the maingraft or legs of the main graft as well as longitudinal or helicalchannels that may provide support as well as a conduit in communicationwith the circumferential channels that may be used for filling thenetwork of inflatable channels with inflation material. Some embodimentsmay also employ radiopaque inflation material to facilitate monitoringof the fill process and subsequent engagement of graft extensions. Thenetwork of inflatable channels 58 may also include one or more one ormore enlarged circumferential channels in the form of inflatable cuffs,such as proximal inflatable cuff 62, which may be configured to seal toan inside surface of a patient's vessel such as a patient's abdominalaorta. Proximal inflatable cuff 62 is disposed on a proximal portion ofthe main graft 12 distal of the proximal anchor member 32 and has anouter surface that extends radially from a nominal outer surface of themain graft 12. The inflatable cuff 62 may be configured to expandradially beyond a nominal outer surface of the main graft 12 and providea seal against an inside surface of a body lumen when the inflatablecuff 62 is inflated with an inflation material to an expanded state. Theaxial separation of the proximal anchor member 32 and proximalinflatable cuff 62 allows for spatial separation of the primaryanchoring mechanism and at least part of the sealing function which mayallow the graft to be restrained or otherwise compressed to a smallerouter profile for deployment from a delivery catheter. An interiorcavity of the inflatable cuff 62 is in fluid communication with theinterior cavity of the remaining network of inflatable channels and mayhave a transverse dimension or inner diameter of about 0.040 inch toabout 0.250 inch.

Some embodiments of main graft member 12 may include about 1 to about 8circumferential inflatable channels disposed about each leg 20 and 26and about 1 to about 8 circumferential channels disposed about a mainbody portion of the main graft member 12. Some embodiments of the maingraft body member 12 may include about 1 to about 4 longitudinal oraxial inflatable channels that may serve to connect the circumferentialinflatable channels. Some embodiments of the circumferential channelsmay extend a full circumference of the graft section upon which they aredisposed, or they may extend only partially around the graft sectionupon which they are disposed. For the main graft member embodiment 12shown in FIG. 1, the network of inflatable channels 58 includes theinflatable cuff 62 disposed adjacent the proximal end of the main bodyportion of the main graft member 12 and a circumferential channeldisposed just distal of the inflatable cuff 62. Each leg 20 and 26 ofthe main graft member 12 includes 3 complete circumferential inflatablechannels in axial series. Each leg 20 and 26 also has two partialcircumferential inflatable channels disposed proximal of the completecircumferential inflatable channels. A longitudinal or axial channelextends substantially along the ipsilateral side of the main graftmember 12 in fluid communication with the fill port 60 andcircumferential channels of the ipsilateral leg 20 and thecircumferential channels and inflatable cuff 62 at the proximal end ofthe main body portion. Another axial channel extends along the entirecontralateral side of the main graft member 12 in fluid communicationwith the cuff 62, circumferential channel at the proximal end of themain body portion and the circumferential channels of the contralateralleg 26.

Some of the inflatable channels of the graft member embodimentsdiscussed herein may be disposed circumferentially and axially such asshown in the embodiment of FIG. 1. Alternatively, such inflatablechannels may be disposed in spiral, helical, or other configurations.Examples of channel configurations suitable for embodiments of thepresent invention are described further in commonly-owned pending U.S.patent application Ser. No. 10/384,103, filed Mar. 6, 2003 and entitled“Kink Resistant Endovascular Graft” to Kari et al., the entirety ofwhich is incorporated herein by reference. All inflatable channelembodiments described herein as circumferential, may alternatively takeon any of the aforementioned alternative configurations. Other modulargraft embodiments are discussed in pending U.S. patent application Ser.No. 11/097,718, 2006/0224232, by Chobotov et al. titled “Hybrid ModularEndovascular Graft”, filed Apr. 1, 2005, which is hereby incorporated byreference herein in its entirety.

The inflatable cuff 62 and other network of inflatable channels 58 maybe filled during deployment of the graft with any suitable inflationmaterial. As discussed above, the inflation material may be used toprovide outward pressure or a rigid structure from within the inflatablecuff 62 or network of inflatable channels 58. Biocompatible gases,liquids, gels or the like may be used, including curable polymericmaterials or gels, such as the polymeric biomaterials described inpending U.S. patent application Ser. No. 09/496,231 filed Feb. 1, 2000,and entitled “Biomaterials Formed by Nucleophilic Addition Reaction toConjugated Unsaturated Groups” to Hubbell et al. and pending U.S. patentapplication Ser. No. 09/586,937, filed Jun. 2, 2000, and entitled“Conjugate Addition Reactions for Controlled Delivery ofPharmaceutically Active Compounds” to Hubbell et al. and furtherdiscussed in commonly owned pending U.S. patent application Ser. No.10/327,711, filed Dec. 20, 2002, and entitled “Advanced EndovascularGraft” to Chobotov, et al., each of which is incorporated by referenceherein in its entirety. Some embodiments may use inflation materialsformed from glycidyl ether and amine materials, as discussed in U.S.patent application Ser. No. 11/097,467, publication number 2006/0222596,filed Apr. 1, 2005, and entitled “Non-Degradable, Low-Swelling, WaterSoluble Radiopaque Hydrogel Polymer” to Askari and Whirley. Someinflation material embodiments may include an in situ formed hydrogelpolymer having a first amount of diamine and a second amount ofpolyglycidyl ether wherein each of the amounts are present in a mammalor in a medical device, such as an inflatable graft, located in a mammalin an amount to produce an in situ formed hydrogel polymer that isbiocompatible and has a cure time after mixing of about 10 seconds toabout 30 minutes and wherein the volume of said hydrogel polymer swellsless than 30 percent after curing and hydration. Some embodiments of theinflation material may include radiopaque material such as sodiumiodide, potassium iodide, barium sulfate, Visipaque 320, Hypaque,Omnipaque 350, Hexabrix and the like. For some inflation materialembodiments, the polyglycidyl ether may be selected fromtrimethylolpropane triglycidyl ether, sorbitol polyglycidyl ether,polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether,diglycerol polyglycidyl ether, glycerol polyglycidyl ether,trimethylolpropane polyglycidyl ether, polyethylene glycol diglycidylether, resorcinol diglycidyl ether, glycidyl ester ether of p-hydroxybenzoic acid, neopentyl glycol diglycidyl ether, 1,6-hexanedioldiglycidyl ether, bisphenol A (PO)₂ diglycidyl ether, hydroquinonediglycidyl ether, bisphenol S diglycidyl ether, terephthalic aciddiglycidyl ester, and mixtures thereof. For some inflation materialembodiments, the diamine may be selected from (poly)alkylene glycolhaving amino or alkylamino termini selected from the group consisting ofpolyethylene glycol (400) diamine, di-(3-aminopropyl) diethylene glycolr, polyoxypropylenediamine, polyetherdiamine, polyoxyethylenediamine,triethyleneglycol diamine and mixtures thereof. For some embodiments,the diamine may be hydrophilic and the polyglycidyl ether may behydrophilic prior to curing. For some embodiments, the diamine may behydrophilic and the polyglycidyl ether is hydrophobic prior to curing.For some embodiments, the diamine may be hydrophobic and thepolyglycidyl ether may be hydrophilic prior to curing.

Other inflation materials that may be used for some embodiments includepolyethylene oxide materials and neopentyl glycol diacrylate materialswhich are discussed in U.S. Pat. Nos. 6,610,035 and 6,176,849, which areincorporated by reference herein in their entirety. U.S. Pat. No.7,147,660 discussed above also includes inflation material embodimentsthat may be used for embodiments discussed herein.

Referring to FIG. 1A, the proximal anchor member 32 may be disposed on aproximal end of the main graft 12 and be secured to the connector ring68 which is at least partially disposed on a proximal portion of themain graft 12. For some embodiments, the connector ring 68 may beembedded in the graft material of the proximal section of the main graft12 and may also be secured by one or more flap elements of a PTFE layeror layers adjacent the connector ring 68. The flaps of adjacent layersmay be folded over the connector ring and secured to the connector ring68, adjacent layers of PTFE material or both. Adhesive materials such asFEP or the like may also be used to secure the connector ring 68 to themain graft body 12. The proximal connector ring 68 has connectorelements 70 extending proximally from the connector ring 68 beyond theproximal end of the graft material of the main graft 12. The connectorelements may be used to couple or be otherwise be secured to matingconnector elements of the proximal anchor member 32 which extenddistally from the distal side of the distal stent 32B of the proximalanchor member 32. The proximal anchor member 32 may have a cylindricalor ring-like configuration generally with elongate elements of theproximal and distal stents 32A and 32B of the anchor member beingpreformed in a serpentine or sine wave pattern of the cylinder. Theproximal anchor member may have a transverse dimension or diameter thatallows for anchoring in a variety of body lumen configurations. Someembodiments of a proximal anchor member 32 which may be suitable for usein a patient's abdominal aorta may have a transverse dimension ordiameter of about 20 mm to about 40 mm. The elongate elements that formthe proximal anchor member 32 may have a radial thickness of about 0.005inch to about 0.040 inch. The width of the elongate elements that formthe proximal anchor member 32 may be from about 0.01 inch to about 0.2inch. U.S. Pat. No. 7,147,660 discussed above also includes anchormember embodiments that may be used for embodiments discussed herein.

The proximal anchor member 32 is secured to the connector ring 68 withflanged connector elements 70 as shown in FIGS. 5A and 5B. The flangedconnector elements 70 may be secured together with wire coils 70Aconfigured to fit between ears of the flanged portions of the connectorelements 70 that have a transverse dimension that is greater than amiddle portion of the connector elements 70. The flanged portionsprovide a pair of opposed surfaces for the coil 70A to seat against andmechanically capture two adjacent connector elements 70 together. Thewire coils 70A used to coupled the flanged elements may have an innertransverse dimension of about 0.005 inch to about 0.050 inch, morespecifically, about 0.010 inch to about 0.030 inch, and have an axiallength of about 2 to about 15 times their diameter, more specifically,about 4 to about 8 times their diameter.

Referring again to FIG. 1A, the proximal stent 32A is coupled to thedistal stent 32B of the proximal anchor member 32 with struts 71disposed between adjacent crowns of the two stents which are shown inmore detail in FIGS. 6A-6D. The struts may be configured such that thecross sectional area of the material of the stents 32A and 32B andstruts remains substantially constant from the proximal portion of thedistal stent to the distal portion of the proximal stent. For someembodiments, the cross sectional area of the material in the area of thestruts 71 is greater than the cross sectional area of either theproximal stent 32B or distal stent 32A adjacent the struts 71. Such aconfiguration may be useful in avoiding stress and strain concentrationsat the junctions between the proximal and distal stents 32A and 32B.

A similar structural configuration may be used at the junction betweenthe connector ring 68 and the distal end of the distal stent 32B. Forthis junction, the struts 72 disposed between the connector ring 68 andconnector elements 70, as shown in FIG. 5A, may have a cross sectionalarea substantially the same as or greater than the cross sectional areaof the connector ring 68 adjacent the connector element 70. In addition,the struts 73 disposed between the distal end of the distal stent 32Band the connector elements 70 of the distal stent 32B may have a crosssectional area that is substantially the same or greater than the crosssectional area of the distal stent 32B adjacent the strut 73. Thisconfiguration may be useful in avoiding stress and strain concentrationsin the junction between the connector ring 68 and the distal stent 32Bof the proximal anchor member 32.

The proximal anchor member 32 and components thereof may have a varietyof configurations which may be collapsible to a small transversedimension or diameter for percutaneous or other types of delivery and beexpandable to engage the inside surface of the patient's vasculature toprovide anchoring to the vasculature and prevent or oppose axialmovement of the anchor member or the graft section attached thereto.Anchor member embodiments 32 may be configured as a self-expandinganchor member having an undulating pattern and may be made fromstainless steel, nickel titanium alloy or any other suitable material.The anchor member 32 may be configured to be balloon expandable orself-expanding in an outward radial direction from a radially compressedstate. The distal anchor member 32 and connector ring 68 may be formedby cutting the configuration of these elements from a single tubularpiece of a selected material, such as the materials discussed above. Theproximal stent 32A of the anchor member 32 may also optionally includebarbs 33 that are angled outwardly from the anchor members and areconfigured to engage tissue of the vessel wall and prevent axialmovement of the anchor members once deployed. The proximal anchor member32 and proximal and distal stents 32A and 32B thereof may have the sameor similar features, dimensions or materials to those of the stentsdescribed in U.S. patent application Ser. No. 10/327,711, US2003/0125797 A1, filed Dec. 20, 2002, by Chobotov et al. which is herebyincorporated by reference in its entirety. The distal stent 32B ofanchor member 32 may also be secured to connector ring 68 in the same orsimilar fashion as described in the incorporated application above.

It may be useful for some embodiments of the main graft 12 to have anominal axial length which is configured to allow the use of the maingraft 12 in a wide variety of vascular morphologies with supplementationby one or more graft extensions 14 and 15. A modular graft embodiment 10is normally chosen in order to have a proper fit to the patient'svasculature. For some graft indications, it is necessary to produce alarge number of size variations of the graft system, or graft assembly10 components, in order to accommodate the size and configurationvariations of each patient's vasculature in order to achieve anacceptable fit of the graft assembly 10 within the patient'svasculature. This can be very costly and time consuming for themanufacturer of the endovascular graft assembly 10 and the hospitalswhich must maintain a comprehensive inventory of the devices. Inaddition, this may require an inconvenient amount of shelf space in thehospital operating room or catheter lab. For some embodiments, maingraft member 12 may have an axial length that is selected to allowanchoring of the proximal anchor member 32 adjacent the renal arteriesextending from a patient's aorta with the legs of the bifurcated portionremaining clear of the iliac arteries in a large cross section ofpatients having diverse physical size and vascular configurations. Inthis way, the need for customizing a graft assembly 10 for a particularpatient or group of patients can be avoided.

For some embodiments, the axial length of the main graft member 12, andparticularly the axial distance or separation between the proximalanchor member 32 and distal end of the ipsilateral and contralaterallegs 20 and 26 may be selected to extend across an abdominal aorticaneurysm without extending into the iliac arteries of a selectedpatient. A selected patient may be a member of a group of patients whohas the longest axial separation between the sealing point in the aortajust distal to the renal arteries and a distal most viable anchor andsealing point in the iliac arteries. In some embodiments for aparticular patient group, the proximal end of the main graft member 12is axially separated from the distal ends of the ipsilateral andcontralateral legs 20 and 26 by a length of about 5 cm to about 10 cm,more specifically, about 6 cm to about 8 cm, as indicated by the arrow74 in FIG. 1.

For some embodiments of sizing a main graft member embodiment 12, theseparation of the proximal anchor member 32 and distal end of deployedgraft extensions 14 and 15 is selected such that the separation is justlong enough to span the separation between the renal arteries and theproximal most anchor and sealing point in the iliac artery or arteriesof a patient. This distance may be determined from the patient, in aselected group of patients, that has the longest such separation in theselected group of patients. In addition, for these embodiments, thisseparation must be shorter than the separation between the renalarteries and hypogastric artery or arteries. The distance may bedetermined from the patient, in the selected group of patients, that hasthe shortest such separation in the selected group of patients. In thisway, it may be possible to treat all members of a selected group ofpatients with a main graft member 12 embodiment or embodiments whichhave a common main graft body length. Such embodiments may be anchoredto the patient's aorta distal of the patient's renal arteries andanchored distally in the patient's iliac artery or arteries, withoutblocking either the renal arteries or hypogastric artery or arteries.Such a modular graft system embodiment 10 may have an overall lengthincluding the main graft member 12 and deployed graft extensions 14 and15 of about 10 cm to about 22 cm, specifically, about 11 cm to about 20cm.

The careful sizing and configuring of the main graft 12 allows the useof a single main graft 12 embodiment or design to be adaptable to a widerange of patients when supplemented by one or more graft extensions 14and 15. More specifically, a main graft 12 having an axial length ofabout 5 cm to about 8 cm may be properly deployed in a large percentageof potential patients. Once deployed, the fluid flow lumens 24 and 30 ofthe ipsilateral and contralateral legs 20 and 26 of the main graft 12can then be sealed to the patient's iliac arteries with the deploymentof graft extensions 14 and 15. Although the graft assembly 10 includesthe option of using attachment elements to secure the graft extensions14 and 15 to the ipsilateral leg and contralateral leg of the main graft12, this may not be necessary in most cases and an adequate seal andmechanical fixation of a graft extensions 14 and 15 may be achieved withthe use of a standard expandable member on the graft extensions 14 and15 instead of an attachment element.

Some embodiments of a method of treating a patient include providing adelivery catheter containing a radially constrained bifurcated maingraft member. The main graft member may be formed from a supple graftmaterial which has a main fluid flow lumen therein and which has anipsilateral leg with an ipsilateral fluid flow lumen in communicationwith the main fluid flow lumen and a contralateral leg with acontralateral fluid flow lumen in communication with the main fluid flowlumen. The main graft member may also include a network of inflatablechannels disposed on the main graft member. Inflatable channels of thenetwork of inflatable channels may be disposed on any portion of themain graft member including the ipsilateral and contralateral legs ofthe main graft member. The main graft member may also include a proximalanchor member which is disposed at a proximal end of the main graftmember and secured to the main graft member. The proximal anchor membermay have a self-expanding proximal stent portion secured to aself-expanding distal stent portion.

Such a delivery catheter may be axially positioned within the patient'svasculature such that the main graft member within the delivery catheteris disposed coextensively with a vascular defect of the patient's aorta.Once this positioning has been achieved, the proximal anchor member maybe deployed so as to engage an inner surface of the patient'svasculature and anchor the proximal anchor member to the patient'saorta. Thereafter, the network of inflatable channels of the main graftmember may be inflated with an inflation material so as to provide amore mechanically rigid structure. For some embodiments, a curable orhardenable fill material may be used that may be cured after inflationof the network of inflatable channels so as to provide additionalmechanical rigidity as well as prevent leakage of the fill material.Some embodiments may also employ radiopaque inflation material tofacilitate monitoring of the fill process and subsequent engagement ofgraft extensions.

A second delivery catheter containing a radially constrainedself-expanding contralateral graft extension may then be axiallypositioned in the contralateral leg of the main graft member with aproximal portion of the contralateral graft extension axially overlappedwith an inner fluid flow lumen of the contralateral leg of the maingraft member and a distal portion of the contralateral graft extensionaxially overlapped with a portion of the patient's contralateral iliacartery. Access to the contralateral leg of the main graft portion may beachieved by percutaneous access or femoral arteriotomy from thepatient's contralateral femoral artery with a delivery sheath or thelike. Once properly positioned, the self-expanding contralateral graftextension may be deployed by releasing the radial constraint of thesecond delivery catheter. As the contralateral graft extension selfexpands in an outward radial orientation, a seal between the inner fluidflow lumen of the contralateral graft extension, a fluid flow lumen ofthe contralateral leg and a fluid flow lumen of the contralateral iliacartery may be formed.

A third delivery catheter containing a radially constrainedself-expanding ipsilateral graft extension may then be axiallypositioned in the ipsilateral leg of the main graft member with aproximal portion of the ipsilateral graft extension axially overlappedwith an inner fluid flow lumen of the ipsilateral leg of the main graftmember and a distal portion of the ipsilateral graft extension axiallyoverlapped with a portion of the patient's ipsilateral iliac artery. Theself-expanding ipsilateral graft extension may then be deployed byreleasing the radial constraint so as to form a seal between the innerfluid flow lumen of the ipsilateral graft extension, a fluid flow lumenof the ipsilateral leg and a fluid flow lumen of the ipsilateral iliacartery.

For some method embodiments of treating the vasculature of a patient, amodular graft assembly, such as the modular graft assembly embodiments10 discussed above, may be used. FIGS. 7-14 illustrate an embodiment ofa deployment sequence of an embodiment of a modular graft assembly. Forendovascular methods, access to a patient's vasculature may be achievedby performing an arteriotomy or cut down to the patient's femoral arteryor by other common techniques, such as the percutaneous Seldingertechnique. For such techniques, a delivery sheath (not shown) may beplaced in communication with the interior of the patient's vessel suchas the femoral artery with the use of a dilator and guidewire assembly.Once the delivery sheath is positioned, access to the patient'svasculature may be achieved through the delivery sheath which mayoptionally be sealed by a hemostasis valve or other suitable mechanism.For some procedures, it may be necessary to obtain access via a deliverysheath or other suitable means to both femoral arteries of a patientwith the delivery sheaths directed upstream towards the patient's aorta.In some applications a delivery sheath may not be needed and thedelivery catheter 75 may be directly inserted into the patient's accessvessel by either arteriotomy or percutaneous puncture.

Once the delivery sheath or sheaths have been properly positioned, adelivery catheter 75 containing a modular graft assembly component, suchas graft member 12, may then be advanced over a guidewire 76 through thedelivery sheath and into the patient's vasculature. In one specificdeployment method embodiment, the main graft member 12 is advancedwithin a delivery catheter 75 through the patient's vessel, typically ina proximal direction from the ipsilateral iliac artery, to a desiredsite of deployment, such as the abdominal aorta, in a constrained statevia a catheter or like device having a low profile and lateralflexibility for ease of delivery through the patient's vasculature. Atthe desired site of deployment, the proximal anchor member 32 of themain graft 12 is released from a constrained state and the proximalanchor member 32 is allowed to expand and secure a portion of the maingraft 12 to the patient's vasculature. Deployment of the modular graftassembly 10 may be carried out by any suitable devices and methods,including techniques and accompanying apparatus as disclosed in U.S.Pat. No. 6,761,733, entitled “Delivery Systems and Methods forBifurcated Endovascular Graft” to Chobotov et al., filed on Jul. 27,2001, and U.S. patent application Ser. No. 11/205,793, entitled“Delivery System and Method for Bifurcated Graft” to Chobotov et al.,filed Aug. 15, 2005, which are incorporated by reference herein in theirentirety.

The delivery catheter 75 may be advanced proximally upstream of bloodflow, as indicated by arrows 77, into the vasculature of the patientincluding the iliac artery 78 and aorta 79 shown in FIG. 7. Othervessels of the patient's vasculature shown in the figures include therenal arteries 80 and hypogastric arteries 81. The delivery catheter 75may be advanced into the aorta 79 of the patient until the main graft 12is disposed substantially adjacent an aortic aneurysm 82 or othervascular defect to be treated. Once the delivery catheter 75 is sopositioned, an outer sheath 83 of the delivery catheter 75 may beretracted distally so as to expose the main graft 12 which has beencompressed and compacted to fit within the inner lumen of the outersheath 83 of the delivery catheter 75 as shown in FIG. 8. In addition tobeing radially compressed when disposed within an inner lumen of theouter sheath 83 of the delivery catheter 75, the proximal stent 32A anddistal stent 32B have been radially restrained by respective highstrength flexible belts 86 in order to maintain a small profile andavoid engagement of the stents 32A and 32B with a body lumen wall untildeployment of the stents 32A and 32B is initiated. The ends of the belts86 may be secured by one or more wires or elongate rods 88 which extendthrough looped ends of the belts 86. Once the outer sheath 83 of thedelivery catheter 75 has been retracted, the delivery catheter 75 andgraft assembly embodiment 10 may be carefully positioned in an axialdirection such that the distal stent 32B is disposed substantially evenwith the renal arteries 80 with the proximal anchor member 32 andproximal sealing cuff 62 positioned proximal of the aneurysm 82. Theproximal anchor member 32 is then deployed and anchored to the patient'saorta 79.

Deployment of the proximal anchor member 32 may begin with deployment ofthe distal stent 32B by retracting the wire or rod 86 that couples endsof belt 88 restraining distal stent 32B. Additional axial positioningmay typically be carried out even after deploying the distal stent 32Bof the proximal anchor member 32. This may still be carried out in manycircumstances as the distal stent portion 32B of the distal anchor 32does not include tissue engaging barbs 33 for some embodiments and willprovide only partial outward radial contact or frictional force on theinner lumen of the patient's vessel 79 until the proximal stent 32A isdeployed. Once the belt 86 constraining the distal stent 32B has beenreleased, the distal stent 32B self-expands in an outward radialdirection until an outside surface of the proximal stent 32B makescontact with and engages an inner surface 90 of the patient's vessel 79as shown in FIG. 9.

After the distal stent 32B has been deployed, the proximal stent 32A maythen be deployed by retracting the wire 88 that couples the ends of thebelt 86 restraining the proximal stent 32B. As the proximal stent 32Aself-expands in an outward radial direction, an outside surface of theproximal stent 32A eventually makes contact with the inside surface 90of the patient's aorta 79. For embodiments that include tissue engagingbarbs 33 on the proximal stent 32A, the barbs may also be oriented andpushed in an outward radial direction so as to make contact and engagethe inner surface tissue 90 of the patient's vessel 79, which furthersecures the proximal anchor member 32 to the patient's vessel 79 asshown in FIG. 10.

Once the proximal anchor member 32 has been secured to the insidesurface 90 of the patient's vessel 79, the proximal inflatable cuff 62may then be filled through the inflation port 60 with inflation materialinjected through an inflation tube 91 of the delivery catheter 75 whichmay serve to seal an outside surface of the inflatable cuff 62 to theinside surface 83 of the vessel 79. The remaining network of inflatablechannels 58 are also filled with pressurized inflation material at thesame time which provides a more rigid frame like structure to the graft12 as shown in FIG. 11. For some embodiments, the inflation material maybe a curable or hardenable material that may cured or hardened once thenetwork of inflatable channels are filled to a desired level of materialor pressure within the network. Some embodiments may also employradiopaque inflation material to facilitate monitoring of the fillprocess and subsequent engagement of graft extensions. The material maybe cured by any of the suitable methods discussed herein including timelapse, heat application, application of electromagnetic energy,ultrasonic energy application, chemical adding or mixing or the like.

The network of inflatable channels 58 may be partially or fully inflatedby injection of a suitable inflation material into the main fill port 60to provide rigidity to the network of inflatable channels 58 and themain graft 12. In addition, a seal is produced between the inflatablecuff 62 and the inside surface of the abdominal aorta 82. Although it isdesirable to partially or fully inflate the network of inflatablechannels 58 of the main graft 12 at this stage of the deploymentprocess, such inflation step optionally may be accomplished at a laterstage if necessary.

Once the graft member 12 is anchored and the inflatable channels 58thereof have been filled and expanded, a second delivery catheter 92that contains the contralateral graft extension 15 may access thecontralateral femoral artery directly or through a delivery sheath asdiscussed above. The second delivery catheter may be advancedproximally, as shown in FIG. 12, until the radially compressedcontralateral graft extension 15 is in an axial position which overlapsthe contralateral leg 26 of the graft member 12. The amount of desiredoverlap of the graft extension 15 with the contralateral leg 26 may varydepending on a variety of factors including vessel morphology, degree ofvascular disease, patient status and the like. However, for someembodiments, the amount of axial overlap between the contralateral graftextension 15 and the contralateral leg 26 may be about 1 cm to about 5cm, more specifically, about 2 cm to about 4 cm. This overlappedposition may also provide for longitudinal overlap between the fluidflow lumen 45 of the graft extension 15 with the fluid flow lumen of thecontralateral leg 26.

Once properly positioned, an outer sheath 94 of the second deliverycatheter 92 which may radially restrain the contralateral graftextension 15, may be distally withdrawn while the graft extension 15remains substantially axially fixed. This axial retraction of the outersheath 94 of the second delivery catheter 92 deploys the contralateralgraft extension 15 so as to allow the graft extension 15 to radiallyself-expand and engage the inner lumen 30 of the contralateral leg 26and inner surface of the contralateral iliac artery proximal of thecontralateral leg 26 as shown in FIG. 13. The graft extension 15 may beso deployed to extend the contralateral leg 20 of the main graft 12 withthe inner lumen 30 of the contralateral leg 26 sealed to the inner lumen45 of the graft extension 15. Once the contralateral graft extension 15has been deployed, the second delivery catheter 92 may be withdrawn fromthe patient's vasculature.

For some embodiments, up to the time that the network of inflatablechannels 58 have been filled with inflation material which has beencured or hardened, an elongate tether 96 may be used to axially restrainthe graft 12 and prevent axial separation of the graft 12 from thedelivery catheter 75. This axial restraint may be important forembodiments wherein the inflation tube 91 of the delivery catheter 75 issecured to the fill port 60 of the network of inflatable channels 58 ofthe graft member 12 by an overlapped slip fit or interference fit only.For some embodiments, the inflation tube 91 may overlap with the filltube 60 of the graft 12 by about 5 mm to about 25 mm, more specifically,about 10 mm to about 15 mm. The tether 96 loops through the flow lumens24 and 30 of the ipsilateral and contralateral legs 20 and 26 of thegraft member 12 and is secured to a handle on a proximal adapter (notshown) of the delivery catheter 75. The tether 96 is configured to havea length that is short enough to mechanically restrain distal axialmovement of the main graft member 12 relative to the delivery catheter75 so as to prevent decoupling of the inflation tube 91 from theinflation or fill port 60 of the main graft member 12. Once theinflation material has been fully injected into the network ofinflatable channels 58 and cured or hardened, the tether 96 may bereleased and removed to allow distal retraction of the delivery catheter75 as shown in FIG. 14.

Once the tether 96 has been released and the delivery catheter 75retracted and decoupled from the graft main member 12 and patient'svasculature generally, a third delivery catheter (not shown) whichcontains the ipsilateral graft extension 14 may be advanced into thepatient's vasculature directly or through an ipsilateral delivery sheathas discussed above. The third delivery catheter may have the samefeatures, dimensions and materials as those of the second deliverycatheter 92. The third delivery catheter may be advanced proximallythrough the patient's femoral artery and into the ipsilateral iliacartery 78 until the radially compressed ipsilateral graft extension 14is in an axial position which overlaps the ipsilateral leg 20 of thegraft member 12. Although not shown, this advancement of the thirddelivery catheter may be carried out in a manner which is the same as orsimilar to the deployment of the second delivery catheter 92 used fordeployment of the contralateral graft extension 15 discussed above. Theamount of desired overlap of the graft extension 14 with the ipsilateralleg 20 may once again vary depending on a variety of factors includingvessel morphology, degree of vascular disease, patient status and thelike. However, for some embodiments, the amount of axial overlap betweenthe ipsilateral graft extension 14 and the ipsilateral leg 20 may beabout 1 cm to about 5 cm, more specifically, about 2 cm to about 4 cm.

This overlapped position may also provide for longitudinal overlapbetween the fluid flow lumen 44 of the graft extension 14 with the fluidflow lumen 24 of the ipsilateral leg 20. Once properly positioned, anouter sheath of the third delivery catheter which may be configured toradially restrain the ipsilateral graft extension 14, may be distallywithdrawn while the graft extension 14 remains substantially axiallyfixed. This axial retraction of the outer sheath of the third deliverycatheter deploys the ipsilateral graft extension 14 so as to allow thegraft extension 14 to radially self-expand and engage the inner lumen ofthe ipsilateral leg 20 and inner surface of the ipsilateral iliac arteryproximal of the ipsilateral leg 20 as shown in FIG. 14. The extension 14may be so deployed to extend the ipsilateral leg 20 of the main graft 12with the inner lumen of the ipsilateral leg 20 sealed to the inner lumen44 of the graft extension 14.

For some deployment embodiments, the patient's hypogastric arteries maybe used to serve as a positioning reference point to ensure that thehypogastric arteries are not blocked by the deployment. Upon such adeployment, the distal end of a graft extension 14 or 15 may be deployedanywhere within a length of the ipsilateral or contralateral leg of thegraft 12. Also, although only one graft extension is shown deployed onthe ipsilateral side and contralateral side of the graft assembly 10,additional graft extensions 14 and 15 may be deployed within the alreadydeployed graft extensions 14 and 15 in order to achieve a desired lengthextension of the ipsilateral leg 20 or contralateral leg 26. For someembodiments, about 1 to about 5 graft extensions 14 or 15 may bedeployed on either the ipsilateral or contralateral sides of the graftassembly 10. Successive graft extensions 14 and 15 may be deployedwithin each other so as to longitudinally overlap fluid flow lumens ofsuccessive graft extensions.

Graft extensions 14 and 15, which may be interchangeable for someembodiments, or any other suitable extension devices or portions of themain graft section 12 may include a variety of suitable configurations.For some embodiments, graft extensions 14 and 15 may include a PTFEcovered helical nitinol stent 51 as discussed above with layers of PTFEhaving a variety of characteristics. Regarding the stent 51, it may beformed from an elongate resilient element which is helically wound witha plurality of longitudinally spaced turns. Some stent embodiments 51may be generally helical in configuration with serpentine or otherregularly space undulations transverse to the helical path of theelongate stent element as shown in more detail in FIG. 15. The ends ofthe stent element may be secured to adjacent ring portions of the stent51 as shown to avoid exposure of element ends to either PTFE graftmaterial or possible patient tissues. The stent element of the stent 51shown in FIG. 15 is a continuous element from one end of the extension14 to the other end thereof. The ends of the elongate element may besecured to adjacent ring members by any suitable means such as adhesivebonding, welding such as laser welding, soldering or the like. For someembodiments, the stent element may have a transverse dimension ordiameter of about 0.005 inch to about 0.015 inch.

For some embodiments of graft extension 14, layers of materials havingdifferent properties may be used in combination to achieve a desiredclinical performance. For example, some layers of PTFE covering thestent 51 may be permeable, semi-permeable or substantially non-permeabledepending on the desired performance and material properties. FIG. 16illustrates a transverse cross sectional view of an embodiment ofextension 14 of FIG. 15 that shows an outer layer of PTFE 54 and aninner layer of PTFE 56. The layers 54 and 56 may be applied by a varietyof methods and have a variety of configurations. For example, some layerembodiments may include extruded tubular structures applied axially overa mandrel or subassembly. Some layer embodiments 54 and 56 may beapplied by wrapping layers circumferentially or wrapping tapes orribbons in an overlapping helical pattern. For some embodiments, theouter layer 54 may be made from or include a semi-permeable orsubstantially non-permeable PTFE layer 100 and the inner layer 56 may bemade of or include a permeable layer of PTFE 102.

The extension 14 may be made by forming the layers of material 100 and102 together with the stent 51 over a mandrel, such as a cylindricalmandrel (not shown). Once the innermost layer 102 of the extension 14has been wrapped about a shaped mandrel, a helical nitinol stent, suchas helical stent 51, may be placed over the innermost layered PTFE layer56 and underlying mandrel. One or more additional layers of lowpermeability PTFE film or PTFE film having substantially no permeability100 that does not have the traditional node fibril microstructure may bewrapped or otherwise added over the exterior of the stent 51. Themandrel may then be covered with a flexible tube such that the film andstent is sandwiched under pressure and sintered so as to raise thetemperature for the PTFE material to undergo a melt transformation inorder to lock in its geometry and strength. The flexible tube (amanufacturing aid not shown) is removed from over the device and theresultant extension is removed from the mandrel.

FIG. 16 illustrates the layered structure of an extension embodiment 14that has been conformed to a mandrel with the layers of PTFE materialover the stent conforming to the stent element so as to form a cohesivestructure. In addition, for some embodiments, an adhesives such as FEPor the like may be applied adjacent the stent prior to the applicationof the PTFE layer covering the stent, or at any other suitable time orlocation, in order to facilitate a bond between the stent element andthe PTFE materials 100 and 102 adjacent the stent 51. For the embodimentof extension 14 shown in FIG. 16, the extension may have the samefeatures, dimensions and materials as those discussed above with regardto the extension embodiment 14 shown in FIGS. 1-6. For some embodiments,the permeable PTFE material 102 may include an ePTFE material havinguniaxial expansion with a uniaxial node fibril structure. PTFE materialshaving a multiaxial node fibril orientation may also be used for someembodiments. For some embodiments, the permeable material 102 mayinclude about 1 to about 5 layers of material or more and have an internodal distance of about 10 microns to about 30 microns. The permeablematerial 102 may have a thickness for some embodiments of about 0.00005inch to about 0.005 inch.

For some embodiments, the low permeability non-expanded PTFE material100 may have a non-typical node fibril microstructure with essentiallyno nodal spacing and very low or no liquid permeability. The extensions14 and 15 may include about 1 layer to about 5 layers of semi-permeableor substantially non-permeable PTFE material having a thickness of about0.0001 inches to about 0.005 inches, more specifically, about 0.0004inches to about 0.001 inches. Examples of such materials are describedin U.S. Patent Application publication numbers 2006/0233990 and2006/0233991 described above which are incorporated by reference intheir entirety herein.

For some embodiments, the PTFE material 100 having low permeability orsubstantially no permeability may be made by providing a PTFE layer andapplying a stretching agent, such as an isopar lubricant material, to atleast a portion of the PTFE layer and stretching the PTFE layer whilethe layer is wet with stretching agent. For some embodiments, the PTFElayer may be saturated with stretching agent while being stretched. Forsome embodiments, the PTFE layer may be stretched by a ratio of about2:1 to about 20:1. For some embodiments, the wet stretching of the PTFElayer is carried out in a direction transverse to the machine directionof expansion. For some embodiments, the wet stretching of the PTFE layeris carried out at a temperature of about 80 degrees F. to about 130degrees F., or at a temperature that is just above the glass transitiontemperature of the PTFE layer material. For some embodiments, the PTFElayer provided is made by extruding a compounded PTFE resin through anextruder to form a PTFE ribbon extrudate. Such a PTFE material 100 mayhave substantially low porosity, low permeability, no discernable nodeand fibril structure and a thickness of about 0.00005 inch to about0.005 inch. Some such PTFE materials may also have a closed cellmicrostructure with a plurality of interconnected high density regionshaving no discernable node and fibril structure between the high densityregions. Some such PTFE materials may have low or no fluid permeability.

FIGS. 17A-17E illustrate schematic representations of several usefulextension configurations 14 in transverse cross section that may havethe same or similar materials, dimensions and features compared to thoseof the embodiment shown in FIG. 16 and the embodiment shown in FIG. 4above. The cross sections shown do not indicate the conformal nature ofthe PTFE layers with the stent structure as shown in FIG. 16, but aremeant to show the number, location and types of PTFE layers with respectto stent 51 for particular embodiments of extensions 14 and 15 and anyother suitable extension embodiments, however, the conformalconfiguration of FIG. 16 may be produced in these embodiments by themethods discussed above. The embodiments of FIGS. 17A-17E are directedto extensions 14 that have low permeability or substantially nopermeability and good structural integrity, particularly in areas wherethe PTFE layer material or materials meet the stent 51.

FIG. 17A illustrates an extension configuration 14 having one or moreinner layers of permeable PTFE material 102 and one or more layers ofsemi-permeable or substantially non-permeable PTFE material 100 disposedbetween the inner layer and the stent 51. One or more layers ofsemi-permeable or substantially non-permeable PTFE material is disposedoutside the stent 51. Each of the layers of PTFE material has beenwrapped, either circumferentially or helically, about itself to form acontinuous tubular structure with overlapping ends or edges. FIG. 17 Billustrates an extension configuration that is substantially the same asthat of FIG. 17A, except that the inner most layer or layers of PTFEmaterial 102 do not connect along a longitudinal or helical lineextending from one end of the extension 14 to the other end of theextension 14 as indicated by the gap in the inner most layer or layersshown in the FIG. 17B. As such, the inner most layer or layers ofextension embodiment 14 of FIG. 17B forms a generally tubular structure,but it is not a closed or complete tubular structure. The tubularstructures formed by the permeable material 102 in FIGS. 17A and 17B mayhave the node fibril direction of the material oriented substantiallyalong the longitudinal axis of the extension 14 for some embodiments.

FIG. 17C illustrates an extension configuration 14 that is alsosubstantially the same as that of FIG. 17A, except that the inner mostlayer or layers of permeable PTFE material are configured as acontinuous extruded tubular structure as opposed to the wrappedstructure indicated for the embodiments in FIGS. 17A and 17B. The layeror layers of semi-permeable or substantially non-permeable material 100on either side of the stent 51 are shown with a helically orcircumferentially wrapped structure with overlapping ends to form acontinuous and closed tubular structure. FIG. 17D illustrates anextension configuration 14 having an extruded tubular inner most layerof permeable material 102 on the inside of the stent 51 and a similarlayer of extruded tubular permeable PTFE material 102 on the oppositeside of the stent 51. The layer or layers of extruded tubular permeablematerial 102 form respective closed and continuous tubular structures oneither side of the stent 51. A layer or layers of semi-permeable orsubstantially non-permeable material 100 is disposed over the outerlayer of permeable material 102 and is wrapped either circumferentiallyor helically with overlapping ends to form a closed tubular structure.

FIG. 17 E illustrates an extension configuration embodiment 14 having aninner tubular structure formed from a layer or adjacent layers of asemi-permeable or substantially non-permeable material 100 disposedadjacent a layer or adjacent layers of permeable material 102 which havebeen wrapped together to form a continuous and closed tubular structuredisposed within the stent 51. The circumferential ends or edges of thelayer of semi-permeable or substantially non-permeable material 100extend circumferentially beyond the circumferential ends or edges of thepermeable material 102. As such, the inner wrapped layers, which may bewrapped either helically or circumferentially, are arranged such thatthe permeable layer 102 never makes contact with itself or the stent 51.

With regard to the above detailed description, like reference numeralsused therein refer to like elements that may have the same or similardimensions, materials and configurations. While particular forms ofembodiments have been illustrated and described, it will be apparentthat various modifications can be made without departing from the spiritand scope of the embodiments of the invention. Accordingly, it is notintended that the invention be limited by the forgoing detaileddescription.

What is claimed is:
 1. A modular endovascular graft assembly,comprising: a bifurcated main graft member formed from a supple graftmaterial including a main fluid flow lumen therein, an ipsilateral legwith an ipsilateral fluid flow lumen in communication with the mainfluid flow lumen, a contralateral leg with a contralateral fluid flowlumen in communication with the main fluid flow lumen and a network ofinflatable channels disposed on the main graft member including theipsilateral and contralateral legs which is configured to accept ahardenable fill material to provide structural rigidity to the maingraft member when the network of inflatable channels are in an inflatedstate and which includes at least one inflatable cuff disposed on aproximal portion of the main graft member configured to seal against aninside surface of a patient's vessel; a proximal anchor member which isformed from a single piece of material, which is disposed at a proximalend of the main graft member, which is secured to the main graft memberand which includes a self-expanding proximal stent portion, aself-expanding distal stent portion, and struts that are disposedbetween adjacent crowns of respective proximal stent portions and distalstent portions, said struts including a cross sectional area that is thesame as or greater than a cross sectional area of either proximal stentportions or distal stent portions adjacent each strut and configured toavoid stress and strain concentrations at junctions between theself-expanding distal stent portion and the self-expanding proximalstent portion; at least one ipsilateral graft extension including afluid flow lumen disposed therein with the fluid flow lumen of the graftextension sealed to and in fluid communication with the fluid flow lumenof the ipsilateral leg of the main graft member; and at least onecontralateral graft extension including a fluid flow lumen disposedtherein with the fluid flow lumen of the graft extension sealed to andin fluid communication with the fluid flow lumen of the contralateralleg of the main graft member.
 2. The graft assembly of claim 1 whereinthe main graft member has an axial length of about 5 cm to about 10 cm.3. The graft assembly of claim 2 wherein the main graft member has anaxial length of about 6 cm to about 8 cm.
 4. The graft assembly of claim1 wherein the fluid flow lumens of the graft extensions are overlappedwith the fluid flow lumens of respective distal legs of the main graftmember.
 5. The graft assembly of claim 1 wherein the proximal stent ofthe proximal anchor member further comprises a plurality of barbs havingsharp tissue engaging tips that are configured to extend in a radialoutward direction in a deployed expanded state.
 6. The graft assembly ofclaim 1 wherein the supple graft material of the main graft and graftextensions comprise layered porous or expanded PTFE.
 7. The graftassembly of claim 1 wherein the graft extensions comprise an interposedself-expanding stent disposed between at least one outer layer and atleast one inner layer of supple layers of graft material and wherein theinterposed stent disposed between the outer layer and inner layer ofgraft material may be formed from an elongate resilient elementhelically wound with a plurality of longitudinally spaced turns into anopen tubular configuration.
 8. The graft assembly of claim 7 wherein theinterposed stent is comprised of a superelastic alloy.
 9. The graftassembly of claim 8 wherein the superelastic alloy comprisessuperelastic NiTi alloy.
 10. The graft assembly of claim 7 wherein thegraft material of each graft extension further comprises at least oneaxial zone of low permeability.
 11. The graft assembly of claim 1wherein the proximal stent portion of the proximal anchor membercomprises a 4 crown stent.
 12. The graft assembly of claim 1 wherein thedistal stent portion of the proximal anchor member comprises an 8 crownstent.
 13. The graft assembly of claim 1 wherein the proximal stentportion and distal stent portion of the proximal anchor member comprisea superelastic alloy.
 14. The graft assembly of claim 13 wherein thesuperelastic alloy comprises superelastic NiTi alloy.
 15. A modularendovascular graft assembly, comprising: a bifurcated main graft memberformed from a supple graft material having a main fluid flow lumentherein, an ipsilateral leg with an ipsilateral fluid flow lumen incommunication with the main fluid flow lumen, a contralateral leg with acontralateral fluid flow lumen in communication with the main fluid flowlumen and a network of inflatable channels disposed on the main graftmember including the ipsilateral and contralateral legs which isconfigured to accept a hardenable fill material to provide structuralrigidity to the main graft member when the network of inflatablechannels are in an inflated state and which includes at least oneinflatable cuff disposed on a proximal portion of the main graft memberconfigured to seal against an inside surface of a patient's vessel; aproximal anchor member which is formed from a single piece of material,which is disposed at a proximal end of the main graft member, which issecured to the main graft member and and which includes a self-expandingproximal stent portion, a self-expanding distal stent portion, andstruts that are disposed between adjacent crowns of respective proximalstent portions and distal stent portions, said struts having a crosssectional area that is the same as or greater than a cross sectionalarea of either proximal stent portions or distal stent portions adjacenteach strut and configured to avoid stress and strain concentrations atjunctions between the self-expanding distal stent portion and theself-expanding proximal stent portion; at least one ipsilateral graftextension having a fluid flow lumen disposed therein with the fluid flowlumen of the graft extension sealed to and in fluid communication withthe fluid flow lumen of the ipsilateral leg of the main graft member;and at least one contralateral graft extension having a fluid flow lumendisposed therein with the fluid flow lumen of the graft extension sealedto and in fluid communication with the fluid flow lumen of thecontralateral leg of the main graft member.
 16. A proximal anchor memberfor anchoring an endovascular graft, comprising: a monolithic structureformed from a single piece of material; a self-expanding proximal stentportion; a self-expanding distal stent portion; and one or more strutswhich are disposed between adjacent crowns of respective proximal stentportions and distal stent portions, said one or more struts including across sectional area that is the same as or greater than a crosssectional area of either proximal stent portions or distal stentportions adjacent each strut and configured to avoid stress and strainconcentrations at junctions between the self-expanding distal stentportion and the self-expanding proximal stent portion.
 17. The proximalanchor member of claim 16 wherein the proximal stent portion, distalstent portion and one or more struts comprise a superelastic alloy. 18.The proximal anchor member of claim 17 wherein the superelastic alloycomprises superelastic NiTi alloy.
 19. The proximal anchor member ofclaim 16 wherein the self-expanding proximal stent portion furthercomprises a plurality of barbs having sharp tissue engaging tips thatare configured to extend in a radial outward direction in a deployedexpanded state.
 20. The proximal anchor member of claim 16 wherein theproximal stent portion comprises a 4 crown stent.
 21. The proximalanchor member of claim 16 wherein the distal stent portion of comprisesan 8 crown stent.